﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp2
{
    class Program
    {
        static void Main(string[] args)
        {
            xbos();
           // kxzxf();
            //sxzfx();
            //jjcfb();
            Console.ReadKey();
        }
        //在 Main 方法中创建一个字符串类型的数组，并存入 5 个值，然后将数组中下标是偶数的元素输出。
        static void xbos()
        {
            string[] a = { "1", "2", "3", "4", "5" };
            for (int i = 0; i < a.Length; i++)
            {
                if (i % 2 == 0)
                {
                    Console.Write(a[i] + "\t");
                }
            }
            Console.WriteLine();
        }
    


        //空心正方形
        //*****
        //*    *
        //*    *
        //*    *
        //*****
        static void kxzfx()
        {
            Console.WriteLine("请输入正方形的边长：");
            int b = int.Parse(Console.ReadLine());
            int[,] a = new int[b, b];
            for (int i = 0; i < a.GetLength(0); i++)
            {
                for (int j = 0; j < a.GetLength(1); j++)
                {

                    if (i == 0 || j == 0 || i == b - 1 || j == b - 1)
                    {

                        a[i, j] = 1;

                    }
                }
            }
            for (int i = 0; i < a.GetLength(0); i++)
            {
                for (int j = 0; j < a.GetLength(1); j++)
                {
                    if (a[i, j] == 1)
                    {
                        Console.Write("*");
                    }
                    else
                    {
                        Console.Write(" ");
                    }
                }
                Console.WriteLine();
            }
        }

        //实心正方形
        //*****
        //*****
        //*****
        //*****
        //*****
        static void sxzfx()
        {
            Console.WriteLine("请输入正方形的边长：");
            int b = int.Parse(Console.ReadLine());

            int[,] a = new int[b, b];

            for (int i = 0; i < a.GetLength(0); i++)
            {
                for (int j = 0; j < a.GetLength(1); j++)
                {
                    a[i, j] = 1;

                }
            }
            for (int i = 0; i < a.GetLength(0); i++)
            {
                for (int j = 0; j < a.GetLength(1); j++)
                {
                    if (a[i, j] == 1)
                    {
                        Console.Write("*");
                    }

                }

                Console.WriteLine();
            }

        }
        //    1 * 1 = 1	
        //2 * 1 = 2	2 * 2 = 4	
        //3 * 1 = 3	3 * 2 = 6	 3 * 3 = 9	
        //4 * 1 = 4	4 * 2 = 8	 4 * 3 = 12   4 * 4 = 16	
        //5 * 1 = 5	5 * 2 = 10	 5 * 3 = 15   5 * 4 = 20	5 * 5 = 25	
        //6 * 1 = 6	6 * 2 = 12     6 * 3 = 18   6 * 4 = 24	6 * 5 = 30	6 * 6 = 36	
        //7 * 1 = 7	7 * 2 = 14	 7 * 3 = 21   7 * 4 = 28	7 * 5 = 35	7 * 6 = 42	7 * 7 = 49	
        //8 * 1 = 8	8 * 2 = 16     8 * 3 = 24	 8 * 4 = 32	8 * 5 = 40	8 * 6 = 48	8 * 7 = 56	8 * 8 = 64	
        //9 * 1 = 9	9 * 2 = 18	 9 * 3 = 27   9 * 4 = 36	9 * 5 = 45	9 * 6 = 54	9 * 7 = 63	9 * 8 = 72	9 * 9 = 81	
        //九九乘法表
        static void jjcfb()
        {
            string[,] a = new string[10, 10];
            for (int i = 1; i <= a.GetLength(0) - 1; i++)
            {
                for (int j = 1; j <= i; j++)
                {
                    a[i, j] = i + "*" + j + "=" + (i * j);
                }

            }
            for (int i = 1; i <= a.GetLength(0) - 1; i++)
            {
                for (int j = 1; j <= a.GetLength(1) - 1; j++)
                {
                    Console.Write(a[i, j] + " ");
                }
                Console.WriteLine();

            }
        }
    }
}
